The present invention relates generally to apparatus for separating flat products from a pile of flat products, and more particularly to an apparatus for separating flat products from a pile of flat products, the apparatus including adjustable separators supporting the bottom of a pile of flat products.
In the technology of creating books, including booklets, magazines, periodicals, and the like, the use of collating systems is well known. These systems typically have a transporting device on which individual flat products, such as signatures or sheets, are gathered to build a book-block set, which then is finished and bound. Typically, a number of feeders are arranged along the transporting device, each of the hoppers comprising a feeding mechanism for feeding an individual flat product from a pile of signatures onto the transporting device, in order to gradually build up the book-block set or to insert a supplement sheet into a pocket of a pocket feeder or into a newspaper arranged in the pocket. Such feeding mechanisms typically employ a sheet-separating device for separating a sheet or other single flat product from a pile of flat products which is arranged in each hopper. The single flat products are drawn from the pile at its bottom end.
A sheet-separating device of this kind is known, for example, from U.S. Pat. No. 3,988,016. This document describes a high-speed paper inserting apparatus for insertion of supplements into newspapers. The inserts are placed to form a stack and a vacuum gripping member grips the lowermost insert from the stack and carries it to a pair of nip rollers which transport the insert to an opened newspaper. A single sheet requires a different sucker stroke than a 120 page or pre-inserted section. The different sucker motion requirements are due to the way the sheets or sections have to be positioned and controlled for proper singulation. Generally, the bottom of the stack is supported by a platform, a so-called signature table having a recess for allowing a sucker to draw a single product from the lowermost end of the pile of products. When the sucker does not contact the pile of products, the pile is supported by a movable hook, as shown in U.S. Pat. No. 4,157,692.
It is an object of the present invention to provide a sheet-separating device with improved separation of the lowermost product of the pile of products.
Commonly-owned U.S. Pat. No. 09/939,428 filed on Aug. 24, 2001 and claiming priority to U.S. Provisional Patent Application No. 60/226,247 filed Feb. 2, 2001, discloses using a plurality of movable needles for selectively supporting the bottom of a stack of signatures, the needles moving in and out of the stack about a pivot point. The penetration depth of the needles is adjustable. U.S. Pat. No. 09/939,428 is hereby incorporated by reference herein.
When the penetration depth of the needles of the ""428 device is adjusted, the contact point of the needles with an edge of the stack can vary, leading to separation problems.
The present invention provides an apparatus for separating flat products from a pile of flat products, the apparatus including a support and at least one separator for separating a product from a pile of products, the separator being movable with respect to the support, the separator including a curved surface for contacting an edge of the pile.
The curved surface permits a penetration depth of the separator to be set by rotation without significantly altering the contact position of the separator and the edge of the pile, which can improve separation.
Preferably, the curved surface defines an arc of a circle. Most preferably, the separator rotates about an axis, and the arc has a constant radius about the axis.
An actuating device can move the separator.
A plurality of separators, for example four or six, spaced along the edge of the pile preferably is provided, the separators being fixed to a rotating block. The rotating block rotates about the axis, and is actuated by the actuating device.
The axis is preferably located below the contact position, so that the curved surface is convex.
The present invention also provides a method for separating a bottom product from a pile of products comprising the steps of:
rotating a separator into the pile, the separator defining a penetration depth; and
adjusting the penetration depth without altering a contact point between an edge of the pile and the separator.
Preferably, the separator includes a curved surface. The curved surface preferably defines an arc of a circle. The separator preferably rotates about an axis, and the arc preferably is defined by a constant radius about the axis. The axis preferably is below the separator so that the curved surface is convex.
The present invention also a method for separating flat products from a pile of flat products comprising the steps of moving at least one separator for separating a product from a pile of products with respect to a support, the separator including a curved surface for contacting an edge of the pile.
Preferably, the curved surface defines an arc of a circle about an axis, the at least separator moving by rotation about the axis.